A conventional tripod of the type used by photographers comprises a tripod hub and three legs pivoted to the hub and arcuately movable from closed positions to extended positions in which all of the legs extend at the same angle with the tripod axis, usually about 40 degrees. The legs are normally composed of two or three telescoping sections so that they can be lengthened at will. Conventional tripods of this type are satisfactory when used on a level surface in that the legs are merely moved to their extended positions and the tripod is positioned on the surface. If it is desired to raise the instrument being supported by the tripod, the extensions on the legs are pulled out by a uniform amount. When however a conventional tripod is used on an irregular surface such as the side of a bank or hill or on a rocky surface, the telescoping sections of the three legs must be extended to different lengths if the head of the tripod is to support the camera in a level position. This operation is time consuming and inconvenient for a photographer who requires the use of a tripod on an uneven terrain. Furthermore, a conventional tripod cannot be positioned on a surface such that the camera is relatively close to the surface; the minimum height is usually that height which is obtained when the camera is positioned on the surface with the leg sections fully telescoped into each other.
The present invention is directed to the achievement of a universal tripod, which, with very little adjustment, can readily be set up on an irregular surface such as a sloping surface or a surface covered with rocks. The invention is further directed to the achievement of a tripod which can be set on a surface such that the head of the tripod, and therefore the camera or other device mounted on the head, is very close to the surface. This feature of the invention is of value to photographers engaged in photographing objects such as flowers or rock formations.
A tripod in accordance with the invention comprises a tripod hub having three tripod legs independently pivoted thereto for arcuate movement between closed positions, in which the legs are clustered around the tripod axis, to extreme extended positions in which each of the legs extend at an angle of about 120 degrees with respect to the tripod axis. A leg clamping means is provided comprising a locking dog for each of the tripod legs and a locking member, or clamping member, movably mounted on the hub for movement between a locking position and an unlocking position. When the locking member is moved to its locking position, the individual locking dogs are simultaneously moved into engagement with their associated tripod legs thereby to lock the legs in the positions they occupy. Moreover, it is merely necessary in setting up the tripod to hold the tripod by the hub with the locking member in its unlocked position and lower the tripod towards the surface so that the legs are splayed outwardly as they come into contact with the surface. The locking member is then moved to its locking position and the legs will be rigidly and securely held against movement so that the tripod will set firmly on the surface.